This invention relates generally to coolers and dryers for agricultural products such as pellets, collets, flakes, meal and expandate products and more particularly to horizontal coolers and dryers with solid pans.
Solid or perforated pan conveyors of existing horizontal cooler/dryers have failed due to the bulk density (weight per cubic foot) of some of these products. These products also generate fines (dust) from normal handling in chutes, bins, conveyors, elevators, etc. Existing solid or perforated pan conveyors have difficulty with fines build-up in the pan louvers or perforations. Pans need to be cleaned routinely to maintain air flow and/or prevent pan damage. Fines leakage into the area between the conveyors can also occur, resulting in high maintenance. If maintenance is not performed as a routine, fines will build up between the conveyors and begin distorting the pans until they reach failure. Performance of internal screws and fines carriers of existing cooler/dryer conveyor designs have not been adequate for handling the large amount of fines found in some products.
Another problem which occurs in existing cooler/dryers is even cooling and/or drying of the product across the conveyor bed. Various plow and gate designs have been used in existing cooler/dryers to spread the product across the conveyor bed. These designs have difficulty controlling bed level resulting in choking or backup of some products. These designs have also damaged some products such as pellets and flakes by crushing (creating more fines).
A further problem in existing cooler/dryers is adequate air seals at the product inlet are difficult to achieve due to the product feeding and leveling mechanism occupying that area. Product inlets require sealing to restrict air flow into the cooler/dryer and fan duct. Some products such as pellets have fat (oil) added before cooling. Oil saturated air will coat the inlet plenum and fan duct resulting in fines build-up. Existing product inlet air seals can cause choking or backup of some products.
The foregoing illustrates limitations known to exist in present horizontal cooler/dryers. Thus, it is apparent that it would be advantageous to provide an alternative directed to overcoming one or more of the limitations set forth above. Accordingly, a suitable alternative is provided including features more fully disclosed hereinafter.